Fluid pumps



Jan. 5, 1965 Filed Jan. 16, 1962 C. HUGHES FLUID PUMPS 3 Sheets-Sheet 1 Jan. 5, -1965 c. HUGHES 3,164,100

FLUID PUMPS Filed Jan. 16. 1962 3 Sheets-Sheet 2 Jan. 5, 1965 c. HUGHES 3,164,100

FLUID PUMPS Filed Jan. 16, 1962 3 Sheets-Sheet 3 United States Patent C) 3,164,100- FLUID PUMPS Cecil Hughes, Chandler-s Ford, near Eastleigh, England,

'assignor to Kelston Engineering Company Limited, Bris tol, England, a company of Great Britain and Northern Ireland Filed Jan. 16, 1962, Ser. No. 166,539 Claims priority, application Great Britain, Jan. 27, 1961, 3,172/61; Feb. 20, 1961, 6,080/61 16 Claims. (Cl. 10S-148) This invention relates .to pumps for fluids and is particularly, although not exclusively, concerned with pumps intended to be used for the conveyance of liquids containing solid suspensions or impurities.

According to the invention there is provided a reciprocating pump, having a liquid chamber with axially extensible and compressible side walls and having a drive member, arranged to close one end of the' chamber whilst reciprocating bodily towards and away from the chamber, so varying the volume of the chamber and driving liquid through the pump; the reciprocating movement being taken up by changes in length of the side walls. More particularly a pump according to the invention may have a body comprising an axially extensible and compressible intermediate casing extending between ported, fixed end covers and a member sealingly secured to said casing intermediate its extent between inlet and outlet chambers of the body, iirst non-return ilow means at the entry to the inlet chamber opening into said chamber, second nonreturn ilow means on said member opening towards the outlet chamber, said member being arranged to reciprocate to vary the volume of the inlet chamber and cause a llow of fluid through the pump. Preferably third nonreturn tlow means are provided adjacent the exit of the outlet chamber and opening to permit flow thereout.

It is possible to produce different ilow characteristics by providing at least one further member carrying nonreturn flow means opening towards the outlet, between said member and the outlet, at least two members of the pump being reciprocable at a different phase, and in a particular aspect of the invention, there is provided a pump having a body comprising ported end covers and an axially extensible and compressible intermediate casing extending between said covers, said casing being fixed relative to said covers intermediate its length to form two portions in series, a member secured to each portion intermediate -its extent to divide the body into inlet and outlet chambers and an intermediate chamber therebetween, respective non-return llow means at the entry to the inlet chamber, between the inlet and intermediate chambers, and between the intermediate and outlet chambers all said means opening for flow towards the outlet, said members being arranged to reciprocate in opposed directions relative to the extent of their associated portions so that the Volumes of the inlet and outlet chambers decrease as the volume of the intermediate chamber increases and vice versa. In such a form of pump it is preferred that the inlet, intermediate and outlet chambers have similar mean volumes.

Advantageously, a pump according to the invention can be arranged so that all the porting through which the uid is to flow is in line so as to reduce the energy losses of the fluid passing through the pump.

The invention will now be more particularly described with reference to the accompanying drawings, wherein:

FIG. 1 is a sectional elevation of a pump according to the invention,

FIG. 2 is a sectional View on the line II-*Il in FIG. l,

FIG. 3 is a scrap view showing a reinforcing ring,

FIG. 4 is an outline elevation showing a pump according to the invention with its driving motor,

3,164,10 Patented Jan. 5, 1'965 ICC FIG. 5 is a sectional elevation of a second pump according to the invention, Y

FIG. 6 is a sectional view across the outer shell on the line VIe-VI in FIG. 5 and FIG. 7 illustrates an alternative form of construction for the flexible casing. y

Referring to FIGS. l to 3, the pump shown there comprises a cylindrical outer casing or shell 2 and inlet and outlet end covers 4, 6 respectively, bolted to the ends of the shell 2 so that they are spaced parallel to each other. Annular grooves 8 in the end covers locate the outer ends of an intermediate cylindrical casing 10 which is axially extensible and compressible and is divided into two equal parts 10a, 10b by a central disc-like impulsion member 12 to dene inlet and outlet chambers 14, 16 respectively, the adjacent ends of the parts 10a, 10b being located in grooves 1S in the member 12. The axial dimensions chosen for the various parts are such that an initial compression is given to the flexible casing 10 when -they are assembled.

symmetrically disposed pairs of ports 20, 22, 24 are arranged in line in the inlet end cover 4, the member 12 and the outlet end cover 6 respectively, as exemplified by the ports 22 in FIG. 2. Associated with each pair of ports are plate valves 26 of neoprene or other suitable material, so that they function as non-return valves permitting ow through the pump from inlet to outlet only, The end covers have threaded bores 28 to receive inlet and outlet connections but, alternatively, they may be flanged for this purpose.

The impulsion member 12 sandwiched between the casing parts 10a, ltlb is capable of axial movement due to the extensibility and compressibility of the parts and, as it moves the volumes of the inlet and outlet chambers 14, 16 will change. Thus, as the volume of chamber 14 increases, a suction will be created opening the valve 26 on the ports 20 to admit uid from a connected source and, at the same time the volume of chamber 16 decreases, the resulting increase in pressure opening the valve 26 on the ports 24 to expel iluid from the outlet of the pump. On the return stroke, the chambers 14, 16 respectively, decrease and increase in volume closing the valves at the inlet and outlet ports 2t), 24, the pressure changes in the two chambers, however, produce a pressure differential which opens the valve on the ports 22 to transfer iluid from the inlet chamber to the outlet chamber. In this manner continued reciprocation of the member 12 provides a positive pumping action.

To actuate the member, a drive shaft 30 extends diametrically through the member and is journalled to opposite sides of the outer shell 2. The shaft carries a pair of eccentrics 32 which have their throws in the same angular position and which iit slide blocks 34 transversely movable in conduits 36 of the member 12,. Rotation of the drive shaft will then reciprocate the member and, since the ports 22 are placed in another portion of the member, there are no sliding-contact interfaces to be sealed from the uid being pumped. Other forms of drive may be employed. In another, unillustrated example, opposed trunnions extend from opposite sides of the member through the outer shelland are coupled to a four bar chain mechanism which will convert the rotary motion of a prime mover into the reciprocating motion required for the member.

Each casing part 10a, 10b is constructed from a series of rings 38 of rubber or a like elastic material between which are interposed relatively rigid rings 40, e.g. of aluminum or other suitable material, the purpose of which is to stabilise the cross-sectional shape of the casing as it is iiexed by movement of the member 12 and by the fluid pressures in the chambers. To this end, the rings 40 can be of I section. Each web 42 abutting adjacent elastic rings 38 canbe relatively thin in the axial direction of the casing to give a Vhigh proportion of elastic material in this direction while the inner and outer flanges 44, 46 are of suliicient strength to provide the necessary support -against distortionof the casing, the outer iiange 46 being of greater thickness than the inner tiange '44. It will be appreciated that the initial vcompression imposed upon the liexible casing should not be completely taken up by the movementof the member 12 for this particular construction of casing cannot transmit tensile forces and there would therefore be some risk of leakage if the movement of thememberfrom its mean position exceeded the initial compression on each part of the casing.

It is possible to operate the pump described above without vproviding a valve at the outlet ports 24. It is found,.however, that when .pumping fluids containing .solid suspensions or impurities the inclusion of this valve can assist -in clearing a transitory obstruction caused by a particleinterfering with the proper closure of one of the other valves which, if .the third valve were not present, could stop the ow completely. j .In FIG. 4 ythere is shown a pump according to the invention connected to inlet pipe 4S and outlet pipe 50. It is driven through coupling 52 by an internal combustion engine 54, the unit being mounted on a common base plate 56. This general arrangement may be employed with the pump describedabove but the pump outlined in this ligure is an alternative from which will now be described with particular reference to FIGS. 5 and 6 of the drawings.

The ,pump illustrated in these figures it. similar in many ways Ito the form already described and where the same parts kare used, they are indicated by their original reference numbers. It will be seen, however, that in this embodiment there are two impulsion members 58, 60 and thus, in addition to .the vinlet and outlet chambers 14, 16 there is an intermediate chamber 62 formed between the two members. A fixed partition 64 integral with outer shell 66 interrupts axially extensible and -compressible casing 68 at the middle of its length and the casing'is thus divided .into four equal parts 68a, 68h, 68e and 68d between which are sandwiched in succession the rst impulsion .member 58, the ,partition64 and the second irnpulsion .member 60. The construction of the casing is in all other respects the same as the casing previously described.

.As before, -inlet and `outlet connections 28 are providedin end covers 70, 72. Pairs of ports 74, '76 of the samelform as the ports 22 shown in FIG. 2 are arranged in the members 58, 60 and a rather larger pair of ports 78 of similar form arearrangedin the partition 64. Plate valves 26 act as non-return valves over the inlet connection and over the ports 74, 76 all opening towards the pump outlet. Of course, the ports 78 are not covered by .a plate valve since they serve to join the two parts of the'intermediatevchamber on veach sideof the partition 64. 1f desired, a further non-return valve can be .provided adjacent the outlet .connection butit is not kas important in .this case as the pump already has three valves. The partition 64 .has a .large `central fairing` 80 radially inwards of the ports 78 which reduces the volume of the intermediate chamber more nearly to those of the 'other two chambers. The yfairing may be shaped to Yafford the minimum resistance to the ilow of the fluid through the intermediate chamber.

The drive `to the pump is transmitted to the coupling 52 iixed to drive shaft 82 projecting diametrically through the central partition 64. Two bearing assemblies fixed to each side of the `shaft `provide three successive pairs of bearings 84, 86, 88. The innermost pair 84 are concentric withthe shaft and are journalled to the outer shell 66. The middle and outer pairs 86, 83 are eccentric to the shaft and each pair is 180 out of phase with the other. Respective pairs of connecting rods 90, 92 connect the bearing pairs 88, 86 to shafts 94,'-96 journalled in the iirst and second impulsion members 5S, et). Thus, rotation of the shaft 82 will reciprocate the members 58, 60 relative to the shell and at out of phase with each other. it will be appreciated that, as with the shaft 30 in the first-described example, the conduits carrying the shafts SZ, 94, 96 are discrete from the interior of the pump.

To explain the effect of providing two succeeding impulsion members which reciprocate in opposed directions it will be convenient to consider their motions starting with the positon shown in FIG. 5 Where the members are shown at the ends of their outward strokes. As the shaft 82 rotates, the eccentric bearing pairs 86, 88 will cause both the members to move towards the central partiiton, increasing the volumes of the inlet and outlet chambers 14, 16 and decreasing the volume of the intermediate chamber 62. Fluid will therefore be drawn into the inlet chamber from the inlet connection. At the same time, the volume of the intermediate chamber is diminishing at twice the rate of the outlet chamber volurne is increasing since the former volume is determined by the movement of both the members and, thus, the excess uid will be expelled from the outlet of the pump. When the members reach the end of their inward strokes and begin to return to their outer positions, the inlet and outlet chambers reduce in volume and further iiuid is expelled from the outlet of the pump. Over this part of the cycle the rate of expansion of the intermediate charnber is twice the rate of contraction of the inlet chamber and, consequently lluid will be drawn through the inlet chamber into the intermediate chamber by suction.

Delivery impulses are thus applied to the liuid over every half cycle and these, in conjunction with the inertia of the fluid ow itself, produce a relatively uniform liow from the pump during operation.

FIG. 7 illustrates an alternative form of intermediate casing that can be used in place of the casing parts 10a, ilb or 68a, 68h, 68C, 63d described. A flexible sleeve 9S of a material such as rubber is reinforced by two series of relatively rigid rings 100, M2 spaced over its inner and outer surfaces respectively. The rings 102 in the outer surface of the sleeve are of larger cross-section than the inner rings ltl. The sleeve is shown attached to rigid end elements 104 which may form integral parts of the impulsion members and end covers already described. Each element has an annular shoulder 166 extending over the end inner faces of the sleeve, a radial projection 198 at the end of each shoulder seating in a corresponding groove in the sleeve to locate the parts which are secured in these positions by hose clips 110. Alternatively or additionally the parts may be secured by being bonded or cemented together. If desired a protective film or lining may be adhered to the inner surface of the sleeve or attached between the sleeve and the shoulders 106 to seal the sleeve from the material being pumped. It will be seen that this form of casing can be designed to carry a tensile load and it is not necessary, therefore, to apply an initial compression to it during assembly of the pump.

In the invention as described above, the pump casing walls are axially extended and compressed as the drive member or members move about their mean positions and this deformation takes place without any significant change in the cross-sectional area of the casing. Under the uctuating axial deformation, the thickness of the resilient wall will alternately increase and decrease, of course, but the effect of this on the volumes of the chambers will be insignificant in comparison with the total internal volume of the pump. Thus, it is possible to say that the total internal volume of a pump according to the invention will remain, for all practical purposes, constant--in contrast, say, to the use of a bellows-form intermediate casing where axial movement would be taken up by flexure of the casing Wall and there would be a marked variation in the total internal volume over the operating cycle.

What I claim and desire to secure by Letters Patent is:

1. A pump comprising, in combination, two spaced end covers and a cylindrical, axially extensible and compressible intermediate casing extending between said covers to define therewith the pump body, inlet and outlet porting in the respective covers, a member axially movable relative to said end covers sealingly secured to said casing intermediate its extent forming inlet and outlet chambers in the body, porting in said member communicating with said chambers, firs-t and second nonreturn iiow means respectively disposed upon said member porting and said inlet porting, said intermediate casing comprising a series of circumferentially directed rigid elements having side bearing surfaces and at least one extensible and compressible elastic element having cylindrical inner yand outer peripheral surfaces engaged at axially spaced intervals by said side bearing surfaces and being radially supported thereby, the rigid elements maintaining the cylindricality of said internal peripheral surface of the casing constant.

2. A pump comprising, in combination, an axially extensible and compressible cylindrical casing formed by a series of spaced, circumferentially directed, rigid elements and at least one elastic element radially supported thereby, said rigid elements co-acting with such elastic elements to maintain the cross-sectional area of the casing constant perpendicular to the axis of deformation, an end cover at each end of said casing defining therewith the pump body, interconnecting means between said covers maintaining said casing in a state of initial compression, a radially extending ported member intermediate said covers sealingly secured to the casing and dividing it into two portions and drive means including a rotary shaft and an interlocking mechanism engaging said shaft and said member to reciprocate the member axially relative to the casing, respective non-return flow means at the ports to said covers and to said member, all said means opening in the same direction of flow.

3. A pump according to claim 2 wherein the intermediate casing comprising a series of elastic rings of rectangular cross-section and said rigid elements are in the form of I-section rings of a relatively rigid material, said rigid rings being interposed between successive elastic rings and each having a web which abuts the adjacent parallel surfaces of successive elastic rings and opposed anges which fit closely the adjacent co-planar surfaces of said rings.

4. A pump according to claim 2 wherein the casing comprises at least two successive cylindrical elastic tubes disposed in series, the member being sandwiched between their adjacent end faces and the series of rigid elements being secured to the inner and outer cylindrical surfaces of said tubes.

5. A pump comprising, in combination, an axially extensible and compressible cylindrical casing formed by a plurality of annular elastic elements each having a substantially cylindrical inner wall and radial restraining means comprising a series of relatively rigid rings bearing against the inner and outer peripheries of said elements to maintain their radial dimensions substantially constant, at least one drive member comprising a radially extending partition and non-return flow means secured thereupon dividing said casing into axial portions, end covers at opposite ends of the casing fixed relative to each other and porting in each cover, non-return flow means positioned at the porting of at least one cover, drive means connected to said at least one drive member reciprocating the member axially and causing a complementary and alternating increase and decrease in the volumes defined by the casing portions on each side of the drive member.

6. A pump according to claim 2 wherein the drive means comprise a drive shaft having a rotary axis fixed relative to the end covers and extending transversely into the member, at least one eccentric on said shaft and a guide located in said member engaging said eccentric.

7. A pump according to claim 2 comprising a second radially extending ported member spaced axially between the rst member and the pump outlet, non-return means secured to said second member and the drive means being connected to both said members to reciprocate them in opposed axial directions. v

8. A pump comprising, in combination, a cylindrical, axially extensible and compressible intermediate casing, fixedly spaced covers at each end thereof having porting for the ow of fluid therethrough, a casing support fixed relative to and intermediate said covers dividing the casing into two portions in series, respective members secured to each portion intermediate its extent to divide the casing into inlet and outlet chambers and an intermediate chamber therebetween, respective non-return valves at the entry to the inlet chamber, between the inlet and intermediate chambers and between the intermediate and outlet chambers, drive means interconnecting said members to reciprocate them in opposed directions relative to each other, the volumes of the inlet and outlet chambers increasing as the volume of the intermediate chamber decreases and vice versa.

9. A pump according to claim 8 wherein the members divide their respective casing portions into two parts of equal axial length and at least one filling element is provided in the intermediate chamber to reduce its free volume, all the chambers thereby having similar mean fluid capacities.

10. A pump according to claim 8 wherein adjacent ends of the casing portions are secured in an axially stressed condition to opposite sides of the casing support, said support extending across the intermediate chamber, porting in said support arranged in line with said nonreturn valves and the outlet porting.

11. A pump according to claim 8 wherein the intermediate casing comprises a series of flexible rings, reinforcing rings of a relatively rigid material being interposed between successive flexible rings.

l2. A pump according to claim 11 wherein the flexible rings are of rectangular cross-section and the reinforcing rings are of I-section, having a web which abuts the adjacent parallel surfaces of succeeding rings and having flanges which fit closely the adjacent co-planar surfaces of said rings.

13. A pump according to claim 8 wherein at least the portions of the intermediate `casing are a continuous sleeve.

14. A pump according to claim 13 wherein there is a series of longitudinally spaced peripheral reinforcing rings secured to the sleeve.

15. A pump according to claim 10 wherein the drive means include a common drive shaft and elements connected between said shaft and the members, the shaft extending transversely through the casing support, a bearing space for the shaft being provided in said support, the interior of said bearing space being discrete from the fluid-filled interior of the pump.

16. A pump comprising, in combination, fixed, ported end members and a peripheral casing wall extending between said end members, two axially spaced, ported drive members dividing the interior of the pump into inlet, intermediate and outlet chambers and a fixed central ported support member secured between the drive members, the casing wall being formed in four cylindrical portions the ends of which are secured to respective adjacent members and the wall structure including a series of cylindrical elements of an axially extensible and compressible material reinforced on their inner and outer peripheries by a series of rigid ring elements to maintain the cylindricality of said portions, non-return valves on and co-acting with the porting of the two drive members and at the inlet end member, drive means including a common power transmission element and respective intermediate elements connecting said common element to drive en- 7 gagement means securedto' the two drive members to reciprocate said drive m'einbes inV op'pdsite direction.

:Referen'lcfes l"Cited by vfthe, Examiner UNITED STATES PATENTS 194,010 8/77 stewart 23o- 160 A 8 1,580,479 4/26 Frankeneid 103--148 2,947,470 8/ 60 Ruben et al 230-160 FOREIGN PATENTS @5,980 12/74 France.

LAURENSE V. EFNER, Primary Examiner.

WARREN E. COLEMAN, Examiner. 

1. A PUMP COMPRISING, IN COMBINATION, TWO SPACED END COVERS AND A CYLINDRICAL, AXIALLY EXTENSIBLE AND COMPRESSIBLE INTERMEDIATE CASING EXTENDING BETWEEN SAID COVERS TO DEFINE THEREWITH THE PUMP BODY, INLET AND OUTLET PORTING IN THE RESPECTIVE COVERS, A MEMBER AXIALLY MOVABLE RELATIVE TO SAID END COVERS SEALINGLY SECURED TO SAID CASING INTERMEDIATE ITS EXTENT FORMING INLET AND OUTLET CHAMBERS IN THE BODY, PORTING IN SAID MEMBER COMMUNICATING WITH SAID CHAMBERS, FIRST AND SECOND NONRETURN FLOW MEANS RESPECTIVELY DISPOSED UPON AND MEMBER PORTING AND SAID INLET PORTING, SAID INTERMEDIATE CASING COMPRISING A SERIES OF CIRCUMFERENTIALLY DIRECTED RIGID ELEMENTS HAVING SIDE BEARING SURFACES AND AT LEAST ONE EXTENSIBLE AND COMPRESSIBLE ELASTIC ELEMENT HAVING CYLINDRICAL INNER AND OUTER PERIPHERAL SURFACES ENGAGED AT AXIALLY SPACED INTERVALS BY SAID SIDE BEARING SURFACES AND BEING RADIALLY SUPPORTED THEREBY, THE RIGID ELEMENTS MAINTAINING THE CYLINDRICALITY OF SAID INTERNAL PERIPHERAL SURFACE OF THE CASING CONSTANT. 